1. Field of Invention
This invention relates to the electrical measurement and testing, and more specifically to instrumentation for detecting and identifying non-metallic objects.
2. Description of the Related Art
Metal detectors are electromagnetic induction devices that induce an electric current in an object to produce a magnetic field. The military relies heavily on metal detectors to locate land mines and explosive devices. Commercially available electromagnetic induction instruments, such as the GEM-3 from Geophex, can detect metal objects with electrical conductivities in a range of greater than 1 million Siemens per meter (S/m).
It is a problem known in the art that electromagnetic induction instruments cannot reliably detect non-metallic or low-metallic objects used to produce weapons and explosives. Nitrogen fertilizer, conductive polymers and carbon fiber are examples of non-metallic substances used to produce deadly explosive devices.
The US military has increased its use of carbon fiber explosive devices in recent years and is expected to continue to do so. Carbon fiber devices do not produce shrapnel and reduce collateral injuries caused by shrapnel. However, the carbon fiber casings cannot be detected by instrumentation known in the art.
There is an unmet need in the art for an electromagnetic induction instrument capable of detecting a wider range of explosive devices.